Plunge-type routers are similar to conventional routers in that they have a drive motor secured within a motor housing. The drive motor has a shaft extending external to the motor housing in a direction toward a base plate attached thereto. A collet or chuck for holding a cutting tool is attached to the external end of the shaft. The motor housing is connected to the base plate by a pair of spatially separated vertical guides.
In conventional types of routers, the motor housing is locked to the vertical guides in a position relative to the base plate such that the cutting tool projects a fixed distance beyond the lower workpiece engaging surface of the base plate at all times. In contrast, plunge-type routers have means for retracting the motor housing so that the cutting tool is above the work engaging surface of the base plate during periods of non-use. In order to enable a plunge-type router to be displaced or "plunged" to the desired cutting depth, adjustable depth stop mechanisms are conventionally provided and may include depth of cut locking mechanisms which lock the position of the router relative to the work engaging surface of the base plate at any desired depth of cut.
Plunge-type routers typically include a pair of handles by means of which the operator may hold and guide the router during use. These handles are also used when the operator "plunges" the router to its desired depth of cut. Once the router is displaced to its desired depth of cut, the motor housing is locked to the vertical guides providing a fixed relationship between the router and the work engaging surface of the base plate. This permits the operator to concentrate on guiding the router without having to worry about the depth of cut.
The invention is a depth of cut locking mechanism for a plunge-type router having a normally locked state which is manually releasable.